Many modern medical therapies require the intravenous (IV) infusion of liquid medicaments into the patient undergoing treatment. Typical liquid medicaments include simple saline solutions, to prevent patient dehydration, solutions containing nutrients for the patient, and solutions that contain medicinal compounds. These liquid medicaments can be infused into the patient by, e.g., gravity drain from an elevated IV bag into the patient, pumping the liquid medicament from a medicament source into the patient, or any other method which is appropriate for the particular therapy and patient.
Ordinarily, the liquid is infused into the patient by connecting the liquid source to one end of an IV line, attaching a needle to the other end of the line, and inserting the needle into the patient. Regardless of how the particular IV infusion therapy is effected, however, the need occasionally arises to infuse other medicaments, in addition to the medicament being infused, into the patient. Commonly, this means that a second needle must be inserted into the patient or injection site. It can be appreciated that this is uncomfortable for the patient and introduces addition hazard to the medical staff. Moreover, the use of needles preferably should be minimized, to minimize the chances of health care workers inadvertently puncturing themselves with needles, which can be especially nettlesome in the era of AIDS.
Accordingly, devices have been developed which permit the infusion of more than one medicament type through a single IV line. For example, connectors familiarly referred to as injection sites ("Y"-site valves or "T"-site valves because of their shape), have been introduced. A Y-site valve has a first port that can be connected to an IV line leading to the source of the liquid medicament to be infused, a second port that can be connected to an IV line leading to the patient, and a third port that can be connected to a second source of liquid medicament. Flow from the first source can be stopped, e.g., by engaging a roller clamp with the IV line leading to the source and then operating the roller clamp to collapse the line, and the infusion of liquid from the second source into the patient can be then be effected through the Y-site valve and the IV line that leads to the patient. Alternatively, a check valve can be positioned just up stream of the Y-site valve or T-site valve.
It is sometimes the case, however, that infusion of a first type of medicament through an IV line into a patient or another IV component, such as an IV bag, cannot immediately precede the infusion of a second type of medicament through the same IV line. This is because some medicaments are not compatible with certain other medicaments. Accordingly, when it is desired to infuse a second medicament into, for example, a patient, through an IV line through which a first medicament has been infused which is incompatible with the second medicament, infusion of the first medicament through the IV line must be halted. Then, a source of flushing fluid or buffer solution must be connected to the Y-site valve, and fluid infused through the Y-site valve and IV line to flush the line.
Next, the source of flushing fluid or buffer solution must be disconnected from the Y-site valve, and the source of the second medicament connected to the valve. Then, the second medicament is infused into the patient. After infusion of the second medicament, the source of the second medicament must be disconnected from the Y-site valve, the IV line flushed again, and the source of the first medicament reconnected to resume the IV therapy.
Understandably, the disconnecting and connecting of a series of IV lines to a single injection site valve can be a time-consuming, labor-intensive evolution, and can also lead to human error in connecting and disconnecting the lines in proper sequence, and potential leaking of the injection site. Such mistakes can not only result in ineffective IV infusion therapy, but can also cause grave complications in the patient.
To address these problems, several syringes have been introduced which have a plurality of chambers, with each chamber being filled with a corresponding liquid, and the syringe can then be used to inject a plurality of liquids into a receptacle. The chambers are separated by plungers which can slide within the syringe, and, as disclosed, e.g., in U.S. Pat. No. 5,102,388 to Richmond, the plungers can be punctured by needles anchored in the next successive plunger after the chamber between the plungers has been exhausted of liquid.
Unfortunately, devices such as the that disclosed in Richmond require the use of sharps in the form of puncturing needles, thus raising the possibility of puncturing personnel whose job it is to fill the chambers with liquids and then position the plungers with sharp needles within the chambers. Further, Richmond and like devices do not provide for connection to a needleless fitting, e.g., the luer fitting of an IV line.
Accordingly, it is an object of the present invention to provide a syringe for infusing a plurality of medicaments into a patient in a predetermined sequence. It is another object of the present invention to provide a syringe which reduces the need to use needles or other sharp components. A further object of the present invention is to provide a syringe for infusing a plurality of liquid medicaments into a patient in a predetermined order, without requiring repeated connections and disconnections of IV lines to an IV connector. Another object of the present invention is to provide a syringe for infusing a plurality of liquid medicaments into a patient in a predetermined order which is easy to use and cost-effective to manufacture.